CN113243142A

CN113243142A - Power supply for LED lighting unit

Info

Publication number: CN113243142A
Application number: CN201980078816.7A
Authority: CN
Inventors: E·J·德默尔; C·滕洪贝格; M·贝杰
Original assignee: Signify Holding BV
Current assignee: Signify Holding BV
Priority date: 2018-11-30
Filing date: 2019-11-19
Publication date: 2021-08-10
Anticipated expiration: 2039-11-19
Also published as: US20210400783A1; JP2022509651A; EP3888422B1; US11540375B2; JP7463370B2; WO2020109068A1; CN113243142B; EP3888422A1

Abstract

A power supply for an LED lighting unit. The power supply comprises two power converters, either of which may provide the power drawn by the components of the LED lighting unit. In particular, the controller of the power supply controls which power converter converts the mains supply to the power level for the connected LED lighting unit. The two power converters are designed to be efficient in providing different power levels.

Description

Power supply for LED lighting unit

Technical Field

The present invention relates to the field of LED lighting units, and in particular to power supplies for LED lighting units.

Background

Lighting units employing light emitting diodes (i.e., LED lighting units) are becoming more and more popular in lighting fixtures or luminaires, often as replacements for the well-known halogen bulbs. The LED lighting unit typically comprises at least one LED arrangement and is switchable between an on-state, in which the LED arrangement outputs light, and an off-state, in which the LED arrangement does not output light.

A recent trend is to include other components in the LED lighting unit to provide additional functionality in addition to pure lighting, such as providing sensing and/or communication functionality. Examples of possible additional components included in the LED lighting unit include: a transmitter; a receiver; a transceiver; a temperature sensor; a motion sensor; an ambient light sensor, etc.

However, it is desirable to continuously provide power to these additional components even when the LED lighting unit is controlled not to emit light. Hence, a concept of a standby state is proposed, in which the LED arrangement is not powered, but other components of the LED lighting unit are powered. This is in contrast to an off-state where all components of the LED lighting unit are not powered.

Existing power supplies for LED lighting units are designed to convert the supply voltage to a power level sufficient to drive the LED unit. This power level is used to drive the LED arrangement (when the LEDs are in a conducting state) and other components of the LED lighting unit (when the LED lighting unit is in a conducting state or a standby state).

Improvements in such power supplies are always desirable.

Disclosure of Invention

The invention is defined by the claims.

According to an example of an aspect of the present invention, there is provided a power supply for an LED lighting unit comprising at least one LED arrangement and at least one other component, the power supply comprising: an input terminal arrangement for receiving a mains supply; an output terminal arrangement adapted to be connectable to an LED lighting unit and to define power supplied to the LED lighting unit when connected thereto; a first power converter designed to convert the received mains supply; a second power converter, separate from the first power converter, designed to convert the received mains supply; a controller adapted to selectively control which of the first power converter and the second power converter converts the mains supply and provides the converted mains supply to the output terminal arrangement, thereby switching the power provided to the connected LED lighting unit between the power converted by the first power converter and the power converted by the second power converter, wherein: when the converted mains supply is at a first non-zero power level, the first power converter is more efficient at converting the mains supply than the second power converter; and the second power converter is more efficient at converting the mains supply than the first power converter when the converted mains supply is at a second, different, non-zero power level.

The proposed arrangement allows two different power converters to provide power to the LED lighting unit at the same output location (e.g. the same pin or node of the output arrangement). By using two separate power converters, specific converters designed for different power levels may be used, enabling efficient conversion of the mains supply at both the first power level and the different second power level to take into account the different power levels drawn by the LED lighting unit. By providing power at the same terminal arrangement (e.g. at the same pin of the output arrangement), the number of wires/connections between the power supply and the LED lighting unit is kept to a minimum.

In other words, each individual power converter may be tuned or designed for a (single) specific power level, enabling the use of an efficient power converter design (e.g., rather than a less efficient variable power converter). This improves the energy efficiency of the overall power supply.

This enables the LED lighting unit to switch between a powered-on or conducting mode/state (in which it draws power for driving all components of the LED lighting unit, including the LEDs) and a standby mode/state (in which it draws power for driving only other components of the LED lighting unit, e.g. not including the LEDs), while continuing to use the efficient power supply.

Each power converter is designed to be more efficient/most efficient when providing a particular power level (e.g., when compared to power converters that provide other power levels). Those skilled in the art will appreciate that different power converters may be designed to be particularly efficient at providing a particular power level when compared to providing other power levels. In particular, different power converters may differ in component values (e.g., inductance/capacitance values) or structure to efficiently provide different power levels. In examples where the power converter includes a transformer, this may result in different power converters having transformers formed from different numbers of windings and/or materials.

The controller is designed to control which power converter provides power to the output terminal arrangement, thereby providing power to the connected LED lighting unit. In other words, the controller may be operable in a first state in which only the output of the first power converter provides power to the output terminal arrangement (and not the output of the second power converter), and a second state in which only the output of the second power converter provides power to the output terminal arrangement (and not the output of the first power arrangement). Thus, the controller may switch which power converter provides the power level to the connected LED lighting unit.

Such control may be performed by controlling whether the output of the power converter is connected to the output terminal arrangement and/or whether the input of the power converter is connected to the input terminal arrangement (e.g. by a switch). Other ways of controlling which power converter provides power to the output terminal arrangement will be apparent to those skilled in the art.

In other words, the first power converter and the second power converter may be connected in parallel with each other and alternately switched/controlled to provide power to the output terminal arrangement.

Of course, in embodiments, the controller may be further operable such that both the first power converter and the second power converter provide power to the output terminal arrangement, and/or such that neither the first power converter nor the second power converter provides power to the output terminal arrangement (e.g. completely turning off the LED lighting unit).

For the avoidance of doubt, it is noted that the first power level and the second power level are different from each other. In other words, the first power converter is designed to be efficient when providing/delivering a first power level (i.e. when the connected LED arrangement draws a first power level), while the second power converter is designed to be efficient when providing/delivering a different second power level (i.e. when the connected LED lighting unit draws a different second power level).

In a specific example, the second power level falls outside a range of ± 1% or ± 5% of the first power level, and vice versa. That is, the difference between the first power level and the second power level may be no less than 1% of the value of the first power level or the second power level. Preferably, the difference between the first power level and the second power level is not less than 90% of the value of the first power level.

In an embodiment, when the converted mains supply is within the first power range, the first power converter is more efficient at converting the mains supply than the second power converter; and when the converted mains supply is within a second, different power range, the second power converter is more efficient at converting the mains supply than the first power converter.

In some embodiments, the second power level may be lower than the first power level. In this way, the first power converter may act as a "high power converter" while the second power converter may act as a "low power converter". Thus, the first power converter may be more efficient at delivering higher power levels (e.g., >0.5W or >5W) than the second power converter.

Preferably, the first non-zero power level is sufficient to power the at least one LED arrangement of the LED lighting unit and the second non-zero power level is insufficient to power the at least one LED arrangement of the LED lighting unit.

In other words, the first power converter may be designed to provide the power drawn by the LED lighting unit in the on-state (e.g. when the LED arrangement is controlled to emit light). The second power converter may be designed to provide a level of power drawn by the LED lighting unit in a standby state (e.g. when the LED arrangement is controlled not to emit light).

In an embodiment, the first power converter is adapted to provide a first non-zero voltage level and the second power converter is adapted to provide a second, different non-zero voltage level.

Thus, the power converters may not only be designed to provide different power levels, but they may also be designed to provide different non-zero voltage levels. This allows two different voltage levels to be controllably provided on the same pin of the output terminal arrangement and thus on the power rail of the LED lighting unit.

Preferably, the first non-zero voltage level is greater than the second non-zero voltage level. Preferably, the first non-zero voltage level is greater than a voltage drop across the LED arrangement of the LED lighting unit and the second non-zero voltage level is less than the voltage drop across the LED arrangement of the LED lighting unit.

Thus, when the second voltage level is provided (from the second power converter), the LED arrangement of the lighting unit may not be able to draw power. This will efficiently turn off the LED arrangement.

In this way, controlling which power converter provides power to the LED lighting unit may control the state of the lighting unit, e.g. whether the LED lighting unit is in an on-state or a standby-state. This enables a simpler LED lighting unit (e.g., without independent control) to be used with the power supply, reducing the cost of replacing the LED lighting unit. In other words, control of the state of the LED lighting unit may be transferred to the power supply.

In an embodiment, the first non-zero voltage level provides a voltage level greater than 25V and the second non-zero power level provides a voltage level less than 10V. In a preferred embodiment, the second non-zero voltage level is a voltage level according to a standard, such as 5V or 3.3V.

In an embodiment, the input terminal arrangement comprises: one or more pins for receiving a mains power supply; an EMI filter circuit adapted to filter a mains power supply; and a surge protection unit for protecting the power supply from surges in the mains power supply.

The controller may be adapted to: determining whether at least one LED arrangement of a connected LED lighting unit is drawing power; and in response to determining that at least one LED arrangement of the connected LED lighting unit is not drawing power, connecting a second power converter to the output terminal arrangement such that the power level provided to the LED lighting unit is maintained at a second non-zero power level. This allows the controller to switch automatically.

Preferably, the first power converter and/or the second power converter comprises a flyback converter. Flyback converters provide efficient converters for generating high power levels.

The controller may comprise a switch adapted to selectively switch the connection of the output terminal arrangement between the output of the first power converter and the output of the second power converter, thereby switching which power converter supplies power to the output terminal arrangement.

Thus, the switch may connect the output terminal arrangement to receive either the power level provided by the first power converter or the power level provided by the second power converter (i.e., and not both). This avoids a potential surge in both power converters affecting or damaging the other power converter.

Examples of the invention may provide a luminaire comprising: any of the power sources; and an LED lighting unit arranged to be connected to an output terminal of the power supply, the LED lighting unit comprising: a power rail adapted to receive a power level from an output terminal arrangement; at least one LED arrangement adapted to receive power from a power rail; and at least one other component adapted to receive power from the power rail.

The at least one LED arrangement may be adapted to require a power level greater than the second power level to emit light, and each of the at least one other component may be adapted to require a power level equal to or less than the second power level to activate.

Thus, the power level required to operate the at least one other component is less than the power level required to operate the LED. To save power, the second power converter may thus provide a different power level (e.g., a lower power level) to power other components when no light output is needed, wherein the second power converter may be designed to suit the power requirements of the second power converter, thereby providing a more efficient system.

Preferably, each at least one LED arrangement comprises a plurality of LEDs connected in series. The at least one other component may comprise a communication unit and/or a sensing unit. Examples include a transmitter; a receiver; a transceiver; a temperature sensor; a motion sensor; an ambient light sensor, etc.

These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

FIG. 1 is a circuit diagram illustrating a power supply according to an embodiment of the present invention; and is

FIG. 2 is a block diagram illustrating a luminaire according to an embodiment of the present invention.

Detailed Description

The present invention will be described with reference to the accompanying drawings.

It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems, and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. It should be understood that the drawings are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to indicate the same or similar parts.

According to the inventive concept, a power supply for an LED lighting unit is proposed. The power supply comprises two power converters, either of which may provide the power drawn by the components of the LED lighting unit. In particular, the controller of the power supply controls which power converter converts the mains supply to the power level for the connected LED lighting unit. The two power converters are designed to be efficient in providing different power levels.

Embodiments are based, at least in part, on the recognition that power converters are more efficient at providing certain power levels than other power levels. Thus, a first power converter may be used when a first power level is required (e.g., for driving both the LEDs and other components of the LED lighting unit), and a second power converter may be used when only a different second power level is required (e.g., for driving only other components of the LED lighting unit, rather than the LEDs). This provides a more efficient and customizable power supply.

For example, the illustrative embodiments may be used in a light fixture or other lighting system.

Fig. 1 shows a circuit diagram of a power supply 1 for a connected LED lighting unit 10 according to an embodiment of the present invention. The following provides a description of an example LED lighting unit 10 to provide a context for embodiments of the present invention.

The LED lighting unit 10 comprises an LED arrangement D3 (e.g. formed by one or more LEDs); an LED switch S3 adapted to control whether the LED arrangement D3 is attempting to draw power to output light (when the LED lighting unit is connected to a power supply); and at least one other component R. The LED arrangement D3 and the at least one other component R are derived from the same power rail P₁Drawing power.

When the LED switch S3 is closed, the LED lighting unit 10 is in an on state (and draws sufficient power to drive the LED arrangement D3 and at least one other component R). When the LED switch S3 is open, the LED lighting unit 10 is in a standby state (and drawing requires sufficient power to drive at least one other component R).

The at least one other component R may include, for example: a processing unit, a control unit, a communication unit and/or a sensing unit. Suitable examples include microprocessors; a transmitter; a receiver; a transceiver; a temperature sensor; a motion sensor; an ambient light sensor, etc. The LED lighting unit 10 may comprise more than one LED arrangement D3 (although only one is shown). Each LED arrangement comprises a string of one or more LEDs, and preferably two or more LEDs.

The power supply 1 comprises a circuit for receiving a mains supply V_in Input terminal arrangement 2. The input terminal arrangement may comprise any standard power terminal (e.g. a 2-pin or 3-pin plug). Here, the mains supply V_inModeled as comprising a grounded 2-output voltage source, and an input terminal arrangement 2 comprising a terminal for connection to a mains supply V_inThe first 2a pin and the second 2b pin.

The power supply further comprises an output terminal arrangement 3. The output terminal arrangement is adapted to provide power to the connected LED lighting unit 10. Here, the output terminal arrangement comprises a first 3a pin and a second 3b pin (including ground) for connection to the LED lighting unit. Other embodiments of the output terminal arrangement may include a different number of pins (e.g., additional pins to provide ground or a three-phase pin out). The output terminal arrangement 3 defines a power rail P provided to the LED lighting unit 10₁Of the power of (c).

The power supply 1 comprises two power converters L1, L2. Each power converter herein comprises a transformer, but alternative power converters are also envisaged, such as a matrix converter or a switched mode power supply.

The first power converter L1 is designed or tuned for supplying the received mains supply V_inTransitioning to a first power level. The second power converter L2 is designed or tuned for supplying the received mains supply V_inTransitioning to a second, different power level. In this way, there are two different power converters designed to provide two respective different power levels.

In particular, when the converted mains supply is at a first non-zero power level, the first power converter is more efficient at converting the mains supply than the second power converter; and the second power converter is more efficient at converting the mains supply than the first power converter when the converted mains supply is at a second, different, non-zero power level.

The power levels may differ by more than 1%, more than 5%, more than 50%, or more than 90%. For example, the difference between the first power level and the second power level may be no less than 1% of the value of the first power level, no less than 5% of the value of the first power level, no less than 50% of the value of the first power level, or no less than 90% of the value of the first power level. In one example, the first power level is in the region of 40W and the second power level is in the region of 0.5W.

The phrase "designed to convert a mains supply to a first power level/a second power level" means that the power converter is designed to be more efficient at converting the mains supply to the first power level/the second power level when compared to providing other power levels. Thus, each power converter L1, L2 may be designed to efficiently provide a particular power level. As is well known to those skilled in the art, efficiency can be measured by comparing the power at the input of the power converter with the (useful) power at the output of the power converter.

It will of course be appreciated that the actual power level provided by the converter may depend on the amount of power drawn by the load connected thereto (especially for simple transformer-based converters that convert a mains supply). However, those skilled in the art will appreciate that different power converters (e.g., having different component values, being formed of different numbers of windings and/or materials, having different structures, etc.) may be designed to be particularly efficient at providing a particular power level, i.e., "designed to convert … to a first power level/second power level.

In an example, when the converted mains supply is within the first power range, the first power converter is more efficient at converting the mains supply than the second power converter; and when the converted mains supply is within a second, different power range, the second power converter is more efficient at converting the mains supply than the first power converter. The first power range includes a first power level and the second power range includes a second power level.

The controller, here comprising the first switch S1 and the second switch S2, controls which power converter L1, L2 provides power to the output terminal arrangement 3, thereby controlling which power converter supplies power to the power rail P of the connected LED lighting unit₁Providing power from the power rail P to the components of the LED lighting unit₁Drawing power. The controller may control connections within the power supply to control which power converter delivers or provides power to the output terminal arrangement.

In particular, the power supply 1 is designed such that the outputs of the first power converter L1 or the second power converter L2 can be connected (directly or via other circuit means) to the same pins of the output terminal arrangement. The controller switches or defines which of the first power converter L1 and the second power converter L2 provides power to the pins of the output terminal arrangement by controlling the connections within the power supply (e.g., opening or closing switches).

Thus, the first and second power converters L1 and L2 are positioned in parallel such that the output of each power converter is provided at the same node or nodes. The power converters are controlled to selectively switch which power converter provides an output at the one or more nodes.

The LED lighting arrangement 10 connected to the output terminal arrangement may thus draw power converted by the first power converter L1 or converted by the second power converter L2 from the same pin 3a of the output terminal arrangement 3.

The switches, such as the first switch S1 and the second switch S2, may be formed of any known switch for interrupting/transferring current, such as a MOSFET or other transistor.

The first diode D1 and the second diode D2 rectify power supplied from the first power converter L1 and the second power converter L2, respectively. A smoothing capacitor C is provided to convert the rectified power (from the first power converter/second power converter) into a DC signal. Thus, diodes D1, D2 and capacitor C effectively act as an AC-DC converter, and may be used to make first power converter L1 and/or second power converter L2 act as flyback converters. For efficiency purposes, certain components, such as capacitor C, may be shared by both power converters.

The diodes D1, D2 and the capacitor C may be replaced by other suitable AC-DC converters or circuit arrangements. For example, the diodes D1, D2 may be replaced by other rectifier circuit devices. In some embodiments, such converters are integrated into the power converters L1, L2, and may be considered to form part of the power converter.

The first power level may be a power sufficient to drive the LED lighting unit in an on-state (e.g. when the LED arrangement D3 is controlled to emit light and the other components R also draw power). The second power level may be a power sufficient to drive the LED lighting unit in a standby state (e.g. when the LED arrangement D3 is controlled to emit no light and only the other components R draw power).

Thus, the second power level may be lower than the first power level. For example, the second power level may be less than 50% or 90% of the first power level. For example, the first power level may be in the region of 40W, while the second power level may be in the region of 0.5W.

In this way, the first power converter may be a "high power converter" and the second power converter may be a "low power converter".

However, the exact values of the first and second power levels will vary depending on implementation details (e.g., based on the characteristics of the LED lighting unit 10 for which the power supply is designed).

The controller may also be configured to operate in a state in which neither the first power supply L1 nor the second power supply L2 provides power to the output terminal arrangement (e.g., both the first power supply L1 and the second power supply L2 are disconnected from the input and/or output). This efficiently places the LED unit in an off state, since the power supply does not provide any power to the LED lighting unit.

From the above, it is clear that the power generated by each power converter can be selectively provided to the output terminal arrangement such that connected LED lighting units 10 can draw power converted by different power converters through the same wires (e.g. at the same power rail).

In the example shown, the output of the power converter is permanently connected to the output terminal arrangement, and the controller controls whether the power converter can be powered from the mains supply V_inDraw/convert power. The first switch S1 controls whether the first power converter L1 draws power from the mains supply. The second switch S2 controls whether the second power converter L2 draws power from the mains supply. Thus, the power converter may be disconnected from the mains supply when controlled not to provide power to the output terminal arrangement. This improves the efficiency of the overall power supply 1.

However, the controller may alternatively control whether the output of the power converters is connected to the output terminal arrangement 3 (e.g. and the input of each power converter may be permanently connected to the input terminal arrangement). For example, in an embodiment, the first switch S1 and the second switch S2 may alternatively be positioned on the other side of the power converter (i.e., the "output side" of the power converter).

In another example, the controller comprises a single switch adapted to switch the connection of the output terminal arrangement between the output of the first power converter and the output of the second power converter (e.g. using a single pole double throw switch). In such embodiments, the input of each power converter may be permanently connected to the input terminal arrangement.

Similarly, in an example, the controller may comprise a single switch adapted to switch the connection of the input terminal arrangement between the input of the first power converter and the input of the second power converter (e.g. using a single pole double throw switch). In such embodiments, the output of each power converter may be permanently connected to the output terminal arrangement.

The controller may further include control logic (not shown), such as a microprocessor or field programmable gate array. The control logic may be adapted to control the operation of the switches S1, S2 (or switches, depending on the embodiment), and may operate, for example, in response to commands or user input. Thus, the control logic may respond to a request to change the state of the LED lighting unit.

In other examples, the control logic may be responsive to a change in the state of the LED lighting unit. For example, if the LED lighting unit switches from an on state to a standby state (e.g. the LED arrangement is off), the control logic can detect the change in state and control the connections to/from the power converters L1, L2 appropriately.

In an example, the control logic may be responsive to the power drawn by the connected LED lighting unit (e.g., sensed by a power meter). In the following embodiments of such examples, it is assumed that the first power level is higher than the second power level.

In such an example, in response to the power drawn by the LED lighting unit being less than the predetermined threshold, the controller may control the connection such that the second power converter provides power to the output terminal arrangement, thereby providing power to the LED lighting unit. In response to the power drawn by the LED lighting unit being greater than a predetermined threshold, the controller may control the connection such that the first power converter provides power to the output terminal arrangement.

The value of the predetermined threshold may be defined by a first power level and a second power level for which the first power converter and the second power converter are designed, respectively. In a simple embodiment, the predetermined threshold may be equal to the value of the second power level for which the second power converter is designed. In another embodiment, the predetermined threshold may be defined by (e.g., equal to) a maximum power level for which the second power converter is more efficient in providing power than the first power converter. Thus, the predetermined threshold may vary based on implementation details.

The predetermined threshold may be subject to hysteresis to account for natural variations in the power drawn and to prevent unnecessary modification by the controller. Thus, there may be a first predetermined threshold defining when the controller switches from providing power to the output terminal arrangement using the first power converter to providing power to the output terminal arrangement using the second power converter, and a second (different) predetermined threshold defining when the controller switches from providing power to the output terminal arrangement using the second power converter to providing power to the output terminal arrangement using the first power converter.

In case the first power converter is designed to provide a higher power level than the power level for which the second power converter is designed, the first predetermined threshold is lower than the second predetermined threshold.

The first and second predetermined thresholds may be defined by a maximum power level for which the second power converter is more efficient in providing power than the first power converter. For example, the first predetermined threshold may be equal to the maximum power level, and the second predetermined threshold may be a set value or percentage that is greater (e.g., 5% greater or 10% greater) than the maximum power level.

In other examples, the first and second predetermined thresholds are defined by a first power level and/or a second power level for which the first/second power converter is designed. For example, the first predetermined threshold may be equal to the second power level, and the second predetermined threshold may be a set value or percentage that is greater (e.g., 5% greater or 10% greater) than the second power level.

In some embodiments, the first and second power levels may be further distinguished from each other by providing different voltage levels to the output terminal arrangement, thereby providing different voltage levels to the connected LED lighting unit 10.

In other words, the first power converter L1 may be designed to provide a first (non-zero) voltage level, while the second power converter L2 may be designed to provide a second, different (non-zero) voltage level. In the case where the power converters each comprise a transformer, the different voltage levels may be provided by using different winding ratios, although other methods are known to those skilled in the art.

In some examples, the first voltage level may be a voltage high enough to drive LED arrangement D3, while the second voltage level may not be high enough to drive LED arrangement D3 (but sufficient to drive other components R).

In particular, the first voltage level may be greater than or equal to the voltage drop across the LED arrangement D3, and the second voltage level may be less than or equal to the voltage drop across the LED arrangement.

By way of explanation, a typical LED arrangement D3 may require a minimum voltage level (e.g., 15V or 45V) to drive it due to the voltage drop across the LED. Thus, if a voltage level below the minimum voltage level is provided to the LED lighting unit, the LED lighting unit may be automatically placed in a standby state (in which the LEDs are not driven) without the need for a control or switch in the LED lighting unit to control whether the LED arrangement draws power from the power rail.

This enables the state of the LED lighting unit to be controlled by controlling which power converter L1, L2 provides power to the LED lighting unit. This efficiently transfers control of the state of the LED lighting unit from the LED lighting unit to the power supply. Thus, the connected LED lighting unit may be simplified (by removing the control system S3 for the LED arrangement D3 from the LED lighting unit).

The exact values of the first voltage level and the second voltage level will vary depending on implementation details (e.g., based on the characteristics of the LED lighting unit 10 for which the power supply is designed).

However, in a preferred embodiment, the first non-zero voltage level is greater than 25V and the second non-zero voltage level is less than 10V. In some examples, the first non-zero voltage level may be 45V and/or the second non-zero power voltage may be about 3.3V or 5V.

In some embodiments, the input arrangement 2 further comprises an EMI (electromagnetic interference) filtering circuit (not shown) adapted to filter the mains power supply; and/or a surge protection unit (not shown) for protecting against surges in the mains power supply. The power converters L1, L2 may be connected to the

pins

2a, 2b of the input arrangement via such additional circuit means and/or further additional circuit means.

Embodiments of the invention may include a luminaire formed of, for example, a power supply 1 and an LED lighting unit 10 connected together.

Fig. 2 is a block diagram illustrating a luminaire 20 according to an embodiment of the present invention. The luminaire 20 comprises a power supply 1 and an LED lighting unit 10. The power supply 1 itself may form an embodiment of the invention.

The power supply 1 comprises an input terminal arrangement 2, an output terminal arrangement 3, a first power converter L1, a second power converter L2 and a controller 5.

The LED lighting unit 10 is connected to the output terminal arrangement 3 of the power supply and comprises a power rail P₁LED arrangement D3 and at least one

other component

12, 13, 15. Power rail P₁Connected to the output terminal arrangement 2 to receive power. The LED arrangement D3 and at least one other component are adapted to draw power from the power rail.

The first power converter L1 and the second power converter L2 of the power supply 1 are each designed for converting a mains supply (not shown) connected to the input terminal arrangement 2 into a respective power level. The controller 5 controls which power converter L1, L2 provides power to the output terminal arrangement 3, thereby providing power to the power rail P of the LED lighting unit 10₁Power is provided. Thus, the controller 5 defines which power converter is on the power rail P₁To provide power.

The at least one

other component

12, 13, 15 may comprise, for example, a communication unit 12 (such as a radio frequency transceiver, transmitter and/or receiver) and/or a sensing unit 13.

In a further embodiment, the luminaire 20 may further comprise a control module 8. The control module may be powered by one of the power converters (e.g., the second power converter L2), even if the power converter does not provide power to the LED lighting unit 10. The control module may be adapted to process the LED lighting unit and/or provide control signals to/from the LED lighting unit.

The control module 8 may form an aspect of the power supply 1.

As part of at least one other component, the LED lighting unit 10 may comprise corresponding control logic 15 for receiving and/or processing control signals for the LED lighting unit 10. For example, the control logic 15 may control the operation of the LED arrangement D3 and/or at least one

other component

12, 13. The control logic 15 may form one of the at least one other components of the LED lighting unit (i.e. it is from the power line P)₁Draw power).

Control logic 15 may receive communications and/or send communications to control module 8The letter is sent. Communication between the control module 8 and the control logic 15 may use any known communication protocol (such as inter-integrated circuit (I)²C) ) is performed.

Although reference/ground lines are present, they are not illustrated for clarity.

Those skilled in the art will be readily able to develop methods for controlling any of the described power supplies or light fixtures, and such methods are contemplated in the present invention. Specifically, a method may include: determining a power level drawn by an LED lighting unit connected to a power supply; and controlling which of the first power converter and the second power converter of the power supply described herein provides the power to be drawn by the LED lighting unit based on the determined power level.

A computer program is also presented, which comprises code means for performing any of the methods described herein, when said program is run on a computer. Thus, different parts, lines or code blocks of a computer program according to embodiments may be executed by a processor/computer to perform any of the methods described herein.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the internet or other wired or wireless telecommunication systems. Any reference signs in the claims shall not be construed as limiting the scope.

Claims

1. A power supply (1) for an LED lighting unit (10), the LED lighting unit (10) comprising at least one LED arrangement (D3) and at least one other component (12, 13, 15, R), the power supply comprising:

input terminal arrangement (2) for receiving a mains supply (V)_in)；

An output terminal arrangement (3) adapted to be connectable to the LED lighting unit and, when connected thereto, to define power provided to the LED lighting unit;

a first power converter (L1, D1, C) designed to convert the received mains supply;

a second power converter (L2), separate from the first power converter, designed to convert the received mains supply;

a controller (S1, S2) adapted to selectively control which of the first and second power converters converts the mains supply and provides the converted mains supply to the output terminal arrangement, thereby switching power provided to the connected LED lighting unit between power converted by the first power converter and power converted by the second power converter,

wherein:

when the converted mains supply is at a first non-zero power level, the first power converter (L1, D1, C) is more efficient at converting the mains supply than the second power converter; and

the second power converter (L2) is more efficient at converting the mains supply than the first power converter when the converted mains supply is at a second, different, non-zero power level.

2. The power supply of claim 1, wherein:

when the converted mains supply is within a first power range, the first power converter (L1) is more efficient at converting the mains supply than the second power converter; and

when the converted mains supply is within a second, different power range, the second power converter (L2) is more efficient at converting the mains supply than the first power converter,

wherein the first power range includes the first power level and the second power range includes the second power level.

3. The power supply of claim 1 or 2, wherein the first non-zero power level is sufficient to power the at least one LED arrangement of the LED lighting unit and the second non-zero power level is insufficient to power the at least one LED arrangement of the LED lighting unit.

4. The power supply of claims 1-3, wherein the first power converter (L1) is adapted to provide a first non-zero voltage level and the second power converter (L2) is adapted to provide a second, different non-zero voltage level.

5. The power supply of claim 4, wherein the first non-zero voltage level is greater than the second non-zero voltage level.

6. The power supply of claim 4 or 5, wherein the first non-zero voltage level is greater than 25V and the second non-zero voltage level is less than 10V.

7. The power supply of claim 4, 5 or 6, wherein the first non-zero voltage level is greater than a voltage drop across the LED arrangement of the LED lighting unit and the second non-zero voltage level is less than a voltage drop across the LED arrangement of the lighting unit.

8. The power supply according to any one of claims 1 to 7, wherein the input terminal arrangement (2) comprises:

one or more pins (2a, 2b) for receiving the mains supply;

-an EMI filter circuit (6) adapted to filter the mains supply; and

a surge protection unit (6) for protecting the mains supply against surges in the power supply.

9. The power supply of any of claims 1-8, wherein the controller is adapted to:

determining whether the at least one LED arrangement of the connected LED lighting unit is drawing power; and

in response to determining that the at least one LED arrangement of the connected LED lighting unit is not drawing power, connecting the second power converter to the output terminal arrangement such that the power level provided to the LED lighting unit is maintained at the second non-zero power level.

10. The power supply of any of claims 1-9, wherein the first power converter (L1, D1, C) comprises a flyback converter.

11. A power supply as claimed in any of claims 1 to 10, wherein the controller comprises a switch adapted to selectively switch the connection of the output terminal arrangement between the output of the first power converter and the output of the second power converter, thereby switching which power converter supplies power to the output terminal arrangement.

12. A luminaire (20) comprising:

the power supply (1) according to any one of claims 1 to 11,

an LED lighting unit (10) connected to the output terminal arrangement of the power supply, the LED lighting unit comprising:

power rail (P)₁) Adapted to receive a power level from said output terminal arrangement;

at least one LED arrangement (D3) adapted to receive power from the power rail; and

at least one other component (12, 13, 15, R) adapted to receive power from the power rail.

13. The light fixture of claim 12, wherein the at least one LED arrangement is adapted to require a power level greater than the second power level in order to emit light, and the at least one other component is adapted to require a power level equal to or less than the second power level in order to activate.

14. The luminaire of claim 12 or 13, wherein each at least one LED arrangement comprises a plurality of LEDs connected in series.

15. The luminaire according to any one of claims 12 to 14, wherein the at least one other component comprises a communication unit and/or a sensing unit.